NAT I Medical Physics With Answers

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NAT I Medical Physics

Sr. # Questions Answers Choice
1 There are discrete energy levels in atoms. It was first experimentally demonstrated by Rutherford's experiment Frank Hertz experiment Marsden's experiment Sommerfield experiment
2 The minimum wavelength of the X-rays produced by electrons accelerated through a potential difference of V volts is directly proportional to √V V<sup>2</sup> 1/√V 1/V
3 The essential distinction between X-rays and y-rays is that y-rays have smaller wavelength than X-rays y-rays emanate from nucleus while X-rays emanate from outer part of the atom y-rays have greater ionizing power than X-rays y-rays are more penetrating than X-rays
4 A photoelectric cell converts Electrical energy to light energy Light energy to light energy Light energy to electrical energy Light energy to elastic energy
5 Ultra-violet radiation of 6.2 eV falls on an aluminium surface K.E of fastest electrons emitted is(work function = 4.2 eV) 3.2 x 10-21 J 3.2 x 10-19 J 7 x 10-25 J 9 x 10-32 J
6 The frequency of the incident light falling on a photosensitive metal plate is doubled the kinetic energy of the emitted photoelectrons is Double the earlier value Unchanged More than doubled Less than doubled
7 A monochromatic source of light is placed at a large distance d from a metal surface Photoelectrons are ejected at rate n,kinetic energy being E. If the source is brought nearer to distance d/2, the rate and kinetic energy per photoelectron become nearly 2n and 2E 4n and 4e 4n and E N and 4E
8 A photocell with a constant p.d of V volt across it illuminated by a point source from a distance of 25 cm. When the source is moved to a distance of 1 m, the electrons emitted by the photocell Carry 1/4th their previous energy Are 1/6th as numerous as before Are 1/4th as numerous as before Carry 1/4th their previous momentum
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